Natural selection, survival of the fittest, this is the basic law of nature. How to choose the evolutionary path of any organism is based on this law.
In the animal world, there are carnivores and herbivores. Carnivores feed on herbivores, while herbivores feed on plants. I believe many friends know that most herbivores, whether small or large, are more docile. When they encounter natural enemies, they will not fight, but turn around and run.
If it’s rabbits and other small animals, it’s normal for them to run away when they meet big and powerful natural enemies. However, we will find that bison, wild horses and other tall and powerful herbivores will not actively choose to fight when they meet predators like wolves, but also turn around and run.
We can imagine how ridiculous it is for a group of bison and sheep to be chased by some smaller wolves. Although it seems a little ridiculous to us, nature is so magical that the instinct on the biological chain is too much suppressed. Even if the land overlord elephant encounters smaller lions and tigers, it does not dare to take the initiative to fight. Instead, it defends passively. Even so, some isolated elephants will be eaten.
So a friend had such a question: Why are herbivores generally not aggressive? Why didn’t nature choose to let them evolve? In our opinion, the reason why herbivores choose to escape when they see carnivores is that these herbivores have not evolved powerful offensive equipment.
Carnivores generally have powerful offensive “equipment”, such as very sharp teeth, strong bite force, sharp claws, etc. But why are such powerful offensive equipment not commonly used in herbivores? Is nature too partial?
As a matter of fact, nature is very fair in the choice of the way of biological evolution. The choice of every way of biological evolution is very fair, and there is no bias. The reason why carnivores have not evolved aggressive equipment is mainly due to their living environment and habits.
As we all know, herbivores feed on vegetation. In order to adapt to the feeding of plants, nature has made them evolve a set of matching body structures. And plants and meat are completely different, vegetation is rich in cellulose, which is a very difficult to digest material. Many carnivores can’t digest it, and they can only excrete it out of the body after eating it. For example, we humans can’t digest this cellulose.
Herbivores are able to digest this kind of cellulose. There are two main reasons for this. One is that their stomach function is very powerful, and they also have multiple stomachs. In addition, the intestines of herbivores are also very long, much longer than those of carnivores.
Long intestine can make food stay for a long time, which is conducive to the digestion of cellulose. Another reason is that the concentration of gastric acid in herbivores is not high. We all know that the concentration of gastric acid in carnivores is very high, which has the advantage of effectively killing microorganisms and preventing various diseases. However, the concentration of gastric acid in herbivores is relatively low, and microorganisms can survive in the body.
Microorganisms have very strong decomposition ability, they can help herbivores decompose cellulose in plants, and convert cellulose into various lipid molecules for herbivores to absorb, which is a mutually beneficial parasitic relationship. Maybe some friends will say that since the low concentration of gastric acid helps to decompose cellulose, isn’t it better for carnivores to reduce the concentration of gastric acid?
In fact, it’s not good at all. Carnivores feed on herbivores, and there are a lot of microorganisms in herbivores, which also enter into carnivores. Microorganisms in herbivores have reached a parasitic relationship in the process of evolution, forming a mutually beneficial relationship, so they will not cause harm to herbivores.
However, they are not friendly to carnivores. Once they enter the body of carnivores, these microorganisms will help to decompose cellulose as well as other healthy cells and tissues, thus posing a threat to the health of carnivores. However, gastric acid can effectively kill these microorganisms. As long as the concentration is high, it can remove them and ensure the health of the meat.
In this respect, the ancestors of human beings were very clever. They learned to drill wood to make fire and cooked food was healthier. After the food is cooked, a large number of microorganisms can be eliminated, so that people will not be threatened by microorganisms after eating. But now some people are constantly trying to eat raw meat, even if the meat is only to eat less than half cooked meat.
In fact, this kind of meat eating habit is very bad. If the meat is not cooked, it is difficult to kill a large number of microorganisms. Once we eat it, we are easy to get sick. So here I would like to advise the majority of friends who like to eat meat, at any time, we should fully cook and roast the meat, not to eat those half cooked, not to eat raw meat.
In order to effectively digest cellulose, herbivores have evolved strong stomachs, long intestines and low concentrations of gastric acid. Whether it’s a more powerful stomach or a longer gut, it consumes a lot of energy. The carnivore’s offensive equipment also needs to consume a lot of energy.
However, the total energy of a creature is limited. In terms of powerful digestive equipment and offensive equipment, only one can be selected. If they choose at the same time, the energy supply will not be available, which is very harmful to the evolutionary health of organisms. This is the choice made by nature for the better survival of organisms.
What’s more, the teeth of herbivores are generally large and flat, rather than small and sharp as those of carnivores. The reason is that herbivores need to grind vegetation into small pieces with their teeth to facilitate stomach digestion and microbial decomposition. At the same time, the eyes of herbivores are very different from those of carnivores.
The eyes of herbivores are on both sides of the head. The advantage of this is that it can expand the field of vision and detect the danger around in time when eating grass. Once there is a natural enemy close, you can find it in time and jump in time. Because herbivores often have to escape, their feet have evolved hooves, and their running ability is also very strong. As long as you can find the natural enemy in time, you can successfully escape most of the time.
In our opinion, the herbivores live a miserable life. When facing the natural enemies, they have no powerful offensive equipment and can only choose to escape. But in fact, the herbivores live a very comfortable life. They rarely worry about food. In nature, vegetation is the most abundant. In the past 500 million years of life, there have been five mass extinctions on the earth, and countless species have disappeared.
But after the mass extinction, the first thing to recover was vegetation, then herbivores, and finally carnivores. In the animal kingdom, herbivores have the most powerful ability to continue. Therefore, in today’s animal kingdom, many older species are basically herbivores.